Frequency response data-based peak filter design applied to MIMO large-scale high-precision scan stage

A large-scale high-precision scan stage is important equipment in the industrial productions of micro-fabrication such as flat panel display (FPD) lithography systems. Designing controllers for multi-input multi-output (MIMO) systems is time-consuming and needs experience because of the interaction between each axis and many controller tuning parameters. The aim of this study is to develop a peak filter design method based on frequency response data to reduce repetitive disturbance. This data-based approach does not use the model and only uses the frequency response data of the controlled system and the disturbance spectrum calculated from the scanning error data (Contribution 1). The peak filter is designed by convex optimization and satisfies robust stability conditions for six-degree-of-freedom systems (Contribution 2). The control performance of the designed peak filter is experimentally demonstrated with an industrial MIMO large-scale high-precision scan stage in reducing the scanning error of the main stroke of the translation along the $x$-axis (Contribution 3).     

5102巷掘进工艺、工序优化研究

为保证在安全的前提下提升小峪煤业5102巷道的掘进速度,通过数值模拟确定了5102巷道掘进支护采用让压分次支护技术,二次支护滞后一次支护的合理距离为20m,现场实施“四·六”制循环作业方式、让压分次支护技术工序平行作业,巷道单日进尺量达到20.2m,保证了5102巷道安全快速掘进。     

Adsorption isotherm and kinetic modeling of a novel procedure for physical modification of silica gel using aqueous solutions of 4,4′-(1,2-ethanediyldinitrilo)bis-(2-pentanone) for preconcentration of Ni(II) ion

ABSTRACT

Aqueous solutions of 4,4′-(1,2-ethanediyldinitrilo)bis-(2-pentanone) (EDDBP) have been used in a novel green procedure for the physical modification of silica gel (SG) for solid-phase extraction and preconcentration of Ni(II) ion. Optimization experiments were carried out at 301 ± 1 K by batch technique. The EDDBP-modified SG was characterized using X-ray Diffraction Spectroscopy (XRD) and Brunaeur-Emmett-Teller (BET) determinations. The adsorption isotherm and kinetic models indicated a physisorption process. The modified SG showed moderate to high adsorption capacity values for Ni(II) ion (~98% removal efficiency) at pH 8. A sorption mechanism for Ni(II) chelation with EDDBP-modified-SG was proposed. These results suggest the procedure has advantages.     

Nonlinear Factor-Augmented Predictive Regression Models with Functional Coefficients

This article introduces a new class of functional-coefficient predictive regression models, where the regressors consist of auto-regressors and latent factor regressors, and the coefficients vary with certain index variable. The unobservable factor regressors are estimated through imposing an approximate factor model on high dimensional exogenous variables and subsequently implementing the classical principal component analysis. With the estimated factor regressors, a local linear smoothing method is used to estimate the coefficient functions (with appropriate rotation) and obtain a one-step ahead nonlinear forecast of the response variable, and then a wild bootstrap procedure is introduced to construct the prediction interval. Under regularity conditions, the asymptotic properties of the proposed methods are derived, showing that the local linear estimator and the nonlinear forecast using the estimated factor regressors are asymptotically equivalent to those using the true latent factor regressors. The developed model and methodology are further generalized to the factor-augmented vector predictive regression with functional coefficients. Finally, some extensive simulation studies and an empirical application to forecast the UK inflation are given to examine the finite-sample performance of the proposed model and methodology.     

Review of pulsed thermal NDT: Physical principles,theory and data processing

This paper summarizes the basics of pulsed thermal nondestructive testing (TNDT) including theoretical solutions, data processing algorithms and practical implementation. Typical defects are discussed along with 1D analytical and multi-dimensional numerical solutions. Special emphasis is focused on defect characterization by the use of inverse solutions. A list of TNDT terms is provided. Applications of active TNDT, mainly in the aerospace industry, are discussed briefly, and some trends in the further development of this technique are described.     

中医药临床研究电子数据管理特点及标准操作规程的制定

电子数据管理具有节约成本、缩短研发周期、提高数据质量等优势,已逐步成为临床研究数据采集与管理的主流形式,规范开展电子数据管理工作是提高中医药临床研究质量的重要措施。本文介绍了临床研究电子数据管理标准操作规程(standard operating procedure, SOP)的作用、制定原则、一般体例、制定流程、SOP的管理与培训以及实际工作中常用的SOP,最后讨论了中医药临床研究电子数据管理的特点及难点,并给出了建议的解决措施。     

Bootstrap procedures for detecting multiple persistence shifts in heteroskedastic time series

This article proposes new bootstrap procedures for detecting multiple persistence shifts in a time series driven by non-stationary volatility. The assumed volatility process can accommodate discrete breaks, smooth transition variation as well as trending volatility. We develop wild bootstrap sup-Wald tests of the null hypothesis that the process is either stationary [I(0)] or has a unit root [I(1)] throughout the sample. We also propose a sequential procedure to estimate the number of persistence breaks based on ordering the regime-specific bootstrap p-values. The asymptotic validity of the advocated procedures is established both under the null of stability and a variety of persistence change alternatives. A comparison with existing tests that assume homoskedasticity illustrates the finite sample improvements offered by our methods. An application to OECD inflation rates highlights the empirical relevance of the proposed approach and weakens the case for persistence change relative to existing procedures.     

Three-dimensional finite element analysis of geosynthetic-reinforced soil walls with turning corners

The paper presents in-depth three-dimensional finite element analyses investigating geosynthetic-reinforced soil walls with turning corners. Validation of the 3D numerical procedure was first performed via comparisons between the simulated and reported results of a benchmark physical modeling built at the Royal Military College of Canada. GRS walls with corners of 90°, 105°, 120°, 135°, 150°, and 180° were simulated adopting the National Concrete Masonry Association guidelines. The behaviors of the GRS walls with corners, including the lateral facing displacement, maximum reinforcement load, factor of safety, potential failure surface, vertical separation of facing blocks, and types of corners were carefully evaluated. Our comprehensive results show (i) minimum lateral displacement occurs at the corner; (ii) lower strength of reinforcements are required at the corner; (iii) higher corner angles lead to lower stability; (iv) potential failure surface forms earlier at the end walls; (v) deeper potential failure surfaces are found at the corners; (vi) larger numbers of vertical separations are found at walls with smaller corner angles. The paper highlighted the salient influence of the corners on the behaviors of GRS walls and indicated that a 3D analysis could reflect the required reinforcement length and the irregular formation of the potential failure surfaces.     

API X52管线钢与Corus RQT 701超高强钢的焊接工艺

针对超高强钢在机械行业的广泛使用,焊接接头易出现淬硬脆化、裂纹等缺陷的情况,采用焊条电弧焊(SMAW)和药芯气体保护焊(FCAW-GS)组合的焊接方法,对API X52管线钢与Corus RQT 701超高强钢的焊接进行了工艺试验,并进行常规力学性能试验。结果表明,通过合理匹配焊接工艺参数,严格控制低热输入量及层间温度,实现了小熔合比的异种钢焊接,且焊接接头具有良好的力学性能,达到了标准和规格书的要求;异种高强钢焊接,采用SMAW打底焊接和FCAWGS填充并盖面的方法,焊接效率较单纯采用焊条电弧焊工艺提高2倍以上。     

Design and analysis of a new wave energy converter based on a point absorber and a hydraulic system harvesting energy from waves near the shore in calm seas

The aim of this paper is to illustrate the design of a new wave energy converter, composed of a point absorber and a hydraulic system (power take off) and sized for recovering energy in calm seas from waves near the shore. The point absorber is consisting of a rectangular shaped buoy integrating a piston pump. The set buoy‐pump oscillates under the waves action and moves natural water in a closed circuit hydraulic system (power take off) composed of a piping connecting the piston pump itself, a pressurized reservoir, a hydraulic turbine and a discharge tank. The methodology adopted for designing the main constituents involves a 1D mathematical model, settled for understanding the motion of the buoy under the hypothesis of regular waves and fully developed sea, and a sizing procedure applied for the design of all the components of the hydraulic system. The project related to the Calabrian site of Cetraro (Mediterranean Sea—south Italy) led to designing a system with a 4 m large buoy, associated with a small 13 cm diameter micro Pelton turbine, so that more than 22 000 kWh could be recovered in a year.